Have you ever wondered how our loyal best friends, the golden retrievers, got their shiny golden coats while most wolves, their closest relatives, only come in darker colours? Scientists have recently unraveled this enigma, the mystery of coat color pattern inheritance in dogs, by discovering a specific genetic variant that causes very light coat colours in dogs and the dazzling white of arctic wolves. It all boils down to a now extinct relative of the modern wolf who lived over two million years ago!
Both wolves and dogs make two different types of coloured pigment, eumelanin responsible for black pigment and pheomelanin responsible for yellow. To generate their coat patterns, there is a precise dance of signaling proteins to enable the production of these two pigments at different places in the body, giving rise to the different coat patterns of dogs and wolves. Several genetic variants had been theorized to cause these patterns, but the use of commercial genetic testing in dogs yielded conflicting results for which variant was truly causing the patterns.
As large libraries of genomes from wolves of different regions became available, researchers used them to further investigate the genetic variants for coat colour that also exist in wolves. From these analyses, researchers concluded that the genetic variants and signaling proteins that cause light-coloured coats were already present in wolves even before domestication. Scientists think that these genetic variants already existed because of their role in facilitating adaptation of wolves to environments during the previous ice ages. Still today, these variants occur in arctic wolves and the light-coloured wolves of the Himalayas.
Want a closer look at some coat patterns of wolves? Check out the Good Stock Library’s Collection to explore beautiful footage of both gray wolves and arctic wolves in North America!